Deep brain stimulation creates information lesion through membrane depolarization

Deep brain stimulation (DBS) is a promising neuromodulation therapy that alters neural activity via intracranial electrical stimulation. However, the neurophysiological mechanisms of DBS remain largely unknown, because of the difficulty of obtaining cellular resolution recordings without electrical interference. Here, we performed high-speed membrane voltage fluorescence imaging of individual hippocampal CA1 neurons during DBS in awake mice. We discovered that DBS, delivered at either 40Hz or 140Hz, reliably depolarizes somatic membrane potentials. Further, DBS enhanced spike rates and paced membrane voltage and spike timing at the stimulation frequency, though more prominent at 40Hz than 140Hz. To determine how DBS induced membrane voltage change impacts neurons ability to process inputs, we optogenetically evoked membrane depolarization. We found that neurons become unreliable in responding to optogenetic inputs during DBS, particularly during 140Hz DBS. These results demonstrate that DBS produces powerful membrane depolarization that interferes with neurons ability to process inputs, creating information lesion.